1990 Cadillac Seville-4 dr

Very good condition. 116K miles. Had brakes replaced. Brake pedal went to the floor first day. Then came back. It's now been 2 months and brake pedal going to the floor again. Have not had to add any fluid to the
master cylinder. Anybody have any ideas what is going on?
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Possibly a bad flexible brake line from frame to wheel? Also could be a bad master cylinder leaking past the piston. You could try taking the cover off the master cylinder and having someone push down on the brake pedal SLOWLY and see if you get bubbles.
There are MANY folks in this newsgroup smarter than me who might have a better idea. It's just the holiday weekend and they are all BBQ-ing.

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I've never seen it be anything but a bad master cylinder. Other possibilities, of course, but IMHO, not as likely. FWIW YMMV DFB
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Well, replaced master cylinder. Brakes are still low. In reading my repair book, it states to bleed the brakes in this order ONLY: right rear, left front, left rear, and THEN right front. I didn't realize that and bled them right rear, left rear, right front, left front....think if I do them again it would make a difference? I hadn't heard of this specific instruction before!
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Your post got my interest. Just looked at the FSM, section 5-14, for my '93 Eldo and it calls for .... 1-Left front 2-Right front 3-Left rear 4-Right rear for either manual bleed or pressure bleed.
The last brake job I did was on my old Econoline and that called for the same sequence you used.
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No laughing....what's a "pressure bleed"?
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A Pressure bleeder uses brake fluid under pressure to bleed the brakes. Just open the bleeder valve and fluid comes flowing out great for 1 person bleeding.

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I'd say you're on the right track.When you said the brakes had been done ,but pedal went to the floor first thing i thought was air still in the brake line.Lots of times (Too often for my money) the brakes aren't bled right so air stays in the brake line.On Mon, 11 Jul 2005

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